The invention relates to a steel coffer for ceiling and/or wall structures, in particular for interior and exterior structures of ships or transportable or easily movable building and housing units.
Steel bulkheads, which in their disposition are essentially used as fire protection or which determine structural stability, have long been known as vertical or horizontal boundaries for spaces in ship construction.
The structural goal is to bridge as large as possible support distances, i.e. bearing widths, and to reduce the number of structural support columns for ceiling structures. At the same time, there is a requirement of creating space for installation of utilities, such as ventilation, water, heating, fire-fighting devices, etc.
For example, steel bulkheads are used as ceiling panels with a sheet metal thickness of 6 to 7 mm, instead of using the required minimum of 5 mm, because the subsequent welding operations cause too great an amount of warping and require appropriate finishing work.
Long stalk, T-shaped support pieces are placed underneath and welded in accordance with static calculations. The free areas of the plates of sheet metal created by this are stiffened by means of special shipbuilding sections. This structure is welded together into building segments which can be moved by a crane and are possibly used more than once in order to create optimum welding positions and prerequisites.
The segments are later combined with other segments and welded together.
A common problem is to make do, along with the least amount of steel used, with as little as possible bracing and twisting of the structure, because of the considerable welding work required.